Field of the Invention
The present invention relates to exhaust gas recirculation (EGR) valves for vehicles and, more particularly, to EGR valves for vehicles which may achieve easy and efficient regulation to keep a balance between the flow rate of exhaust gas to be introduced into an engine through an EGR flow channel and the flow rate of fresh air from the outside.
Description of the Related Art
Generally, in order to restrict production of nitrogen oxide (NOx) from exhaust gas discharged from engines of vehicles, the most frequently used method at present is the use of exhaust gas recirculation (EGR) valves that add some cooled exhaust gas to a mixer, causing the same to be suctioned into a cylinder.
Considering a configuration of such an EGR valve, as disclosed in Korean Patent Laid-Open Publication No. 2010-107494, the EGR valve includes a fresh air flow channel for introduction of outside fresh air and an EGR flow channel for guidance of exhaust gas discharged from an engine to allow the exhaust gas to be returned and reintroduced into the engine.
Here, the fresh air flow channel is provided with a fresh air regulation valve and the EGR flow channel is provided with an EGR regulation valve.
The EGR regulation valve and the fresh air regulation valve are linked to each other via power transmission means, such as gears, and an actuator connected to the power transmission means, rather than being separately moved.
In the aforementioned related art, when the EGR regulation valve is completely closed, the fresh air regulation valve is arranged parallel to a flow direction of fresh air. This arrangement minimizes obstruction of introduction of fresh air by the fresh air regulation valve and, in turn, allows fresh air to be introduced into the engine while maintaining the maximum flow rate thereof.
Then, when the EGR regulation valve is opened to a given degree for reintroduction of exhaust gas into the engine, the fresh air regulation valve is simultaneously moved to partially block a cross sectional area of the fresh air flow channel, thereby serving to reduce the inlet amount of fresh air per hour.
Then, when the EGR regulation valve is completely opened, the fresh air regulation valve reaches a maximum closed state thereof, thereby further reducing the amount of fresh air to be introduced into the engine.
In the related art as described above, the fresh air regulation valve and the EGR regulation valve are indirectly connected to each other via power transmission means, such as gears or cams. Damage to the power transmission means, such as gears or cams, may prevent efficient linked operation between the fresh air regulation valve and the EGR regulation valve, which may in turn causes the fresh air regulation valve or the EGR regulation valve to have difficulty in regulating the flow rate of fresh air or exhaust gas.
In addition, due to the fact that a valve plate and a valve rotating shaft are located in the fresh air flow channel, a stream of fresh air should pass the valve plate and the valve rotating shaft, which disadvantageously causes deterioration in the inlet pressure and inlet amount of fresh air even if the fresh air flow channel is opened by 100%.